drm/amd/display: remove unused variables dispclk_delay_subtotal and dout

clang with W=1 reports
drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn314/display_rq_dlg_calc_314.c:1003:15:
  error: variable 'dispclk_delay_subtotal' set but not used [-Werror,-Wunused-but-set-variable]
        unsigned int dispclk_delay_subtotal;
                     ^
This variable is not used, so remove it.
Which made dout unused, so also remove.

Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>